The fundamental purpose of a health insurance exchange is to provide a structured marketplace for the sale and purchase of health insurance. The authority and responsibilities of an exchange may vary, depending on statutory or other requirements for its establishment and structure. The Patient Protection and Affordable Care Act requires health insurance exchanges to be established in every state by January 1, 2014. The ACA provides certain requirements for the establishment of exchanges, while leaving other choices to be made by the states. Qualified individuals and small businesses will be able to purchase private health insurance through exchanges. Issuers selling health insurance plans through an exchange will have to follow certain rules, such as meeting the private market reform requirements in the ACA. While the fundamental purpose of the exchanges will be to facilitate the offer and purchase of health insurance, nothing in the ACA prohibits qualified individuals, qualified employers, and insurance carriers from participating in the health insurance market outside of exchanges. This book outlines the required minimum functions of exchanges, and explains how exchanges are expected to be established and administered under the ACA. The coverage offered through exchanges is discussed, and the book concludes with a discussion of how exchanges will interact with selected other ACA provisions.